In conventional networks, such as wireless networks, peer devices need to be authenticated before they are permitted access to the network. A number of standards have developed to govern the authentication of peer devices and to control access to networks. For example, IEEE standard 802.11i defines certain security protocols for wireless network access and authentication, and IEEE 802.1X provides a port-based authentication framework for 802 LANs, and, in particular, wireless local area networks (WLANs) that conform to the IEEE 802.11 standard. IEEE 802.1X can be implemented using a standard authentication protocol framework, such as the Extensible Authentication Protocol (EAP) defined in RFC 3748.
EAP defines an authentication framework rather than the actual authentication method. Within EAP, there are a number of methods/mechanisms that may be employed to conduct the authentication exchange. These may be referred to as EAP-specific authentication methods or mechanisms. Examples include EAP-TLS, EAP-SIM, EAP-AKA, PEAP, LEAP and EAP-TTLS.
During an EAP-specific authentication exchange, master session keys (MSKs) are generated by the peer and the server. At the server-side, an associated key lifetime is also generated. The MSKs may be later used to derive additional keys, including transient session keys (TSKs)—also called pairwise transient keys (PTKs). These derived PTKs or TSKs will share the same key lifetime limitations of the MSKs. If the EAP authentication exchange is successful, an EAP success message is sent from the server to the peer, often via an intermediary authenticator associated with the access port.
When the PTK or TSK lifetime expires, the authenticator must de-authenticate the peer device from the network. The peer device is required to repeat the authentication process. This de-authentication, and consequent disconnection from the access point, may be highly undesirable if the peer device is engaged in an active session. For example, in voice-over-IP (VoIP) and other such communication applications, the disconnection may result in dropped phone calls. In other applications, media sessions may be disrupted and data packets may be lost as a result of the disconnection.
Accordingly, it would be advantageous to provide an improved method and system for peer device authentication.